The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
While numerous sterilization processes and devices are known, most are not well suited for sterilizing food powder and other food-based materials. This is due, in part, to the fact that food material is sensitive and easily damaged (e.g., its composition can be easily changed).
For example, while the medical industry frequently utilizes high pressure and/or high temperature vessels (e.g., autoclaves) to sterilize medical instruments, sterilizing food material in this manner would substantially alter the composition of the food material.
Other industries, such as the pharmaceutical industry, utilize radiation-based sterilization rather than high pressure/temperature sterilization processes to avoid damaging or altering highly sensitive pharmaceutical formulations. Unfortunately, radiation-based sterilization processes may also damage food material.
Other industries use shock wave sterilization processes to sterilize matter without producing excessive heat. See, for example, PCT/US2010/049248 and U.S. Pat. No. 5,588,357. Unfortunately, high shock pressures can also degrade food material.
U.S. Pat. No. 4,756,882 (Jacobs) describes a sterilization process in which objects are contacted with hydrogen peroxide, and trace amounts of residual hydrogen peroxide are subjected to plasma treatment to generate an active species. The active species are effective to kill microbes. Any residual hydrogen peroxide simply converts into non-toxic decomposition products. This sterilization process may be used with food material.
While the plasma sterilization process described in Jacobs can be used to sterilize food materials, the systems and devices described in Jacobs are intended for batch processing, and are therefore not well suited to sterilizing large volumes of food material.
Thus, there is still a need for improvements in plasma sterilization devices and methods.